RICHARD III (Duke of Gloucester):

Which line in this excerpt from act I, scene I, of Richard III is a stage direction?

And if King Edward be as true and just
As I am subtle, false and treacherous,
This day should Clarence closely be mew'd up,
About a prophecy, which says that 'G'
Of Edward's heirs the murderer shall be.
Dive, thoughts, down to my soul: here
Clarence comes.
(Enter CLARENCE, guarded, and BRAKENBURY)
Brother, good day; what means this armed guard
That waits upon your grace?

GEORGE PLANTAGENET (Duke of Clarence): His majesty
Tendering my person's safety, hath appointed
This conduct to convey me to the Tower.

RICHARD III (Duke of Gloucester): Upon what cause?